Sun dial



Feb. 14, 1967 J- P. BLANKS 3,303,567

SUN DIAL Filed Nov. 1, 1963 INVENTOR.

JOHN P- BLAAIKS A TORHEY United States Patent This invention relates to an improvement in sun dials whereby to adjust the usual hour band and has for its purpose the provision of a compensating cam that is designed to be used with heliochronometer type solar instrument.

The object of the invention is to provide a means to compensate the hour band through the medium of a cam and when the cam is turned, the hour band which is biased toward the cam will move back and forth. This movement will compensate the hour band for the equation of time so that the shadow cast by the gnomon rod on the hour band will convert solar time to true clock time.

The hour band is provided with a slot having an adjustable set screw whereby the device may be set for longi tude and daylight saving.

Novel features of construction and operation of the device will be more clearly apparent during the course of the following description, reference being had to the accompanying drawings wherein has been illustrated a preferred form of the device and wherein like characters of reference are employed to denote like parts throughout the several figures.

-Referring to the drawings:

FIGURE 1 is a fragmentary horizontal section taken through a mounting frame for the sun dial and showing the invention applied thereto with respect to the hour band and the adjustable means therefor,

FIGURE 2 is a transverse section taken substantially on line 2-2 of FIGURE 1,

FIGURE 3 is a plan view of the compensating cam, and

FIGURE 4 is a section on line 4-4 of FIGURE 1.

Referring specifically to the drawings there has been illustrated a frame 5 that is notched at 6. Overlying the frame and the notch 6, is a conventional hour band 7, that is provided with numerals 8 corresponding to the hours of the day. The hour band 7 is slotted at a substantial length intermediate its width as indicated at 9. Adjustably engaged through the slot 9 is a cylindrical stud 10. The stud 10 includes a cylindrical sleeve 11 that is threaded upon a screw 12 and with the head of the screw 13 spanning the slot 9 and whereby the stud may be loosened for adjustment along the slot 9. The notch 6 forms a clearance for the passage of the stud 10.

Adapted to engage the stud 10, is a cam device 14. The cam device, see particularly FIGURE 3, is divided into twelve sectors and with each sector carrying indicia indicative of the months of the year as indicated at 15 and with each sector having radial division lines 16 and with the marginal edge of each sector being provided with indicia indicating the days of the month, shown at 17. The cam 14 is pivotally supported at 18 upon a bolt 19 that extends through a flat bracket plate 20. The bracket .plate 20 is provided with a lateral extension 21, that is bent downwardly to form a lip 22. The lip 22 is fixed to the side of the frame 5, by screws 23. Fixed to the top of the frame 5, is a screw 24, that overlies the marginal edge of the band 7 and whereby to maintain the hour band against shifting laterally of the frame 5.

In the use of the device, it is understood that a gnomon rod is provided to cast a shadow upon the hour band 'ice as is customary in devices of this type. Means have heretofore been provided to move the hour band in accordance with the change of seasons and months but these means have been relatively complicated and confusing to the average person who has a sun dial. With the cam device 14, having the various divisions indicating the months and with the divisions being designated as to days of the month, it becomes relatively simple to move the hour band and to adjust the hour band for a particular month and date. When the hour band is to be adjusted for longitude or daylight saving, the cam is rotated and the stud 10 loosened and shifted along the slot 9 so as to move the hour band in accordance with the particular time area or longitude.

The device is extremely simple and is easily adjusted both as to months and days and for both longitude and daylight saving.

It is to be understood that the invention is not limited to the precise construction shown, but that changes are contemplated as readily fall within the spirit of the invention as shall be determined by the scope of the subjoined claims.

I claim:

1. In a sun dial of the type that is provided with an upstanding frame that carries a gnomon rod and a declination band, an arcuate hour band that is connected at its opposite ends to a ring that is pivoted on the frame, the hour band extending transversely of the upstanding frame and adapted to be shifted in a transverse path for varying the time as would be cast upon the hour band by the gnomon rod, the hour band being provided with an elongated slot inter-mediate its width, a stud engageable in the slot and with the stud adapted to be clamped with respect to the hour band and with the stud extending below the slot, a cam device that is supported upon the frame and with the cam device having its marginal edge engageable with the stud and whereby to shift the hour band in accordance with the time to be ascertained, a bracket .plate that is fixed on one side of the frame and with the cam pivotally supported on the bracket plate.

2. The structure according to claim 1 wherein the face of the cam is divided into twelve segments, the segments being indicated by radial lines from the pivotal point of the cam, each of the segments along the marginal edge of the cam being additionally divided by radial lines equidistantly spaced apart and with the last named lines having indicia corresponding to days of the month, each segment being provided with indicia indicating the months of the year, the cam being rotatable to cause its marginal edge to engage the stud and to shift the hour band in accordance with the month and the day and means fixed to the upstanding frame and overlying the hour band to prevent lateral shifting of the band during its traverse movement across the frame under the influence of the cam.

References Cited by the Examiner UNITED STATES PATENTS 196,550 10/1877 Anderson 3362 825,319 7/1906 Hewitt 33-62 2,754,593 7/1956 Sundblad 3362 FOREIGN PATENTS 8,134 1839 Great Britain.

130,410 12/1950 Sweden.

ROBERT B. HULL, Primary Examiner. 

1. IN A SUN DIAL OF THE TYPE THAT IS PROVIDED WITH AN UPSTANDING FRAME THAT CARRIES A GNOMON ROD AND A DECLINATION BAND, AN ARCUATE HOUR BAND THAT IS CONNECTED AT ITS OPPOSITE ENDS TO A RING THAT IS PIVOTED ON THE FRAME, THE HOUR BAND EXTENDING TRANSVERSELY OF THE UPSTANDING FRAME AND ADAPTED TO BE SHIFTED IN A TRANSVERSE PATH FOR VARYING THE TIME AS WOULD BE CAST UPON THE HOUR BAND BY THE GNOMON ROD, THE HOUR BAND BEING PROVIDED WITH AN ELONGATED SLOT INTERMEDIATE ITS WIDTH, A STUD ENGAGEABLE IN THE SLOT AND WITH THE STUD ADAPTED TO BE CLAMPED WITH RESPECT TO THE HOUR BAND AND WITH THE STUD EXTENDING BELOW THE SLOT, A CAM DEVICE THAT IS SUPPORTED UPON THE FRAME AND WITH THE CAM DEVICE HAVING ITS MARGINAL EDGE ENGAGEABLE WITH THE STUD AND WHEREBY TO SHIFT THE HOUR BAND IN ACCORDANCE WITH THE TIME TO BE ASCERTAINED, 